Table of Contents

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  1. Preface
  2. Working with Transformations
  3. Aggregator Transformation
  4. Custom Transformation
  5. Custom Transformation Functions
  6. Data Masking Transformation
  7. Data Masking Examples
  8. Expression Transformation
  9. External Procedure Transformation
  10. Filter Transformation
  11. HTTP Transformation
  12. Identity Resolution Transformation
  13. Java Transformation
  14. Java Transformation API Reference
  15. Java Expressions
  16. Java Transformation Example
  17. Joiner Transformation
  18. Lookup Transformation
  19. Lookup Caches
  20. Dynamic Lookup Cache
  21. Normalizer Transformation
  22. Rank Transformation
  23. Router Transformation
  24. Sequence Generator Transformation
  25. Sorter Transformation
  26. Source Qualifier Transformation
  27. SQL Transformation
  28. Using the SQL Transformation in a Mapping
  29. Stored Procedure Transformation
  30. Transaction Control Transformation
  31. Union Transformation
  32. Unstructured Data Transformation
  33. Update Strategy Transformation
  34. XML Transformations

Transformation Guide

Transformation Guide

Sharing a Named Lookup Cache

Sharing a Named Lookup Cache

You can also share the cache between multiple Lookup transformations by using a persistent lookup cache and naming the cache files. You can share one cache between Lookup transformations in the same mapping or across mappings.
The Integration Service uses the following process to share a named lookup cache:
  1. When the Integration Service processes the first Lookup transformation, it searches the cache directory for cache files with the same file name prefix.
  2. If the Integration Service finds the cache files and you do not specify to recache from source, the Integration Service uses the saved cache files.
  3. If the Integration Service does not find the cache files or if you specify to recache from source, the Integration Service builds the lookup cache using the database table.
  4. The Integration Service saves the cache files to disk after it processes each target load order group.
  5. The Integration Service uses the following rules to process the second Lookup transformation with the same cache file name prefix:
    • The Integration Service uses the memory cache if the transformations are in the same target load order group.
    • The Integration Service rebuilds the memory cache from the persisted files if the transformations are in different target load order groups.
    • The Integration Service rebuilds the cache from the database if you configure the transformation to recache from source and the first transformation is in a different target load order group.
    • If you do not configure the first Lookup transformation in a target load order group to recache from source, and you do configure the subsequent Lookup transformation to recache from source, the Integration Service does not rebuild the cache.
    • If the cache structures do not match, the Integration Service fails the session.
If you run two sessions simultaneously that share a lookup cache, the Integration Service uses the following rules to share the cache files:
  • The Integration Service processes multiple sessions simultaneously when the Lookup transformations only need to read the cache files.
  • The Integration Service fails the session if one session updates a cache file while another session attempts to read or update the cache file. For example, Lookup transformations update the cache file if they are configured to use a dynamic cache or recache from source.

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